Oxysilylene fluorochemical polymers and process for preparing same

ABSTRACT

An oxysilylene fluorochemical polymer is prepared by reacting (a) at least one fluorochemical diol containing two pairs of trifluoromethyl groups, each pair being attached directly to a carbon atom having a hydroxy group attached thereto, and (b) at least one silylamino compound having two amino groups each attached directly to a silicon atom; or, reacting a dialkali metal salt of the diol with a corresponding dichloride of the silylamino compound. The preferred fluorochemical diols include the isobutylene and propylene adducts of hexafluoroacetone, and the preferred silylamino compounds include 1,4bis(dimethylaminodimethylsilyl)benzene and bis(dimethylamino) dimethylsilane.

' United States Patent Tanquary [54] OXYSILYLENE FLUOROCHEMICAL POLYMERSAND PROCESS FOR PREPARING SAME [72] Inventor: Albert Charles Tanquary,Birmingham, Ala.

[73] Assignee: Southern Research Institute, Birmingham, Ala.

22 Filed: Aug. 18, 1970 21 Appl.No.: 64,811

[52] US. Cl. ..260/2 S, 117/ l6l ZA, 260/37 SB,

260/46.5 G, 260/46.5 P, 260/47 R, 260/4482 D, 260/448.8 R [51] Int. Cl...C08i 11/04 [58] Field of Search 260/2 S, 46.5 P, 47 R, 448.8 R,

[ 1 Sept. 12, 1972 Breed ..260/33.6 Gall ..260/2 [5 7] ABSTRACT Anoxysilylene fluorochemical polymer is prepared by reacting (a) at leastone fluorochemical diol containing two pairs of trifluoromethyl groups,each pair being attached directly to a carbon atom having a hydroxygroup attached thereto, and (b) at least one silylamino compound havingtwo amino groups each attached directly to a silicon atom; or, reactinga dialkali metal salt of the diol with a corresponding dichloride of thesilylamino compound. The preferred fluorochernical diols include theisobutylene and propylene adducts of hexafluoroacetone, and thepreferred silylamino compounds include 1,4-bis(dimethylaminodimethylsilyl)benzene and bis( dimethylamino)dimethylsilane.

12 Claims, No Drawings BACKGROUND OF THE INVENTION 1 Field'of theInvention The present invention relates to oxysilylene fluorochemicalpolymers and to processes for making them.

2. Summary of the Prior Art Since their discovery, synthetic resins orpolymers such as the silicon-containing and fluorine-containing polymershave found wide application in industries and scientific disciplines inmany forms such as coatings, shaped articles and binders. See, forexample, US. Pat. Nos. 2,800,494, 3,346,515, and 3,493,546. However, thesearch has continued, particularly in the aerospace industries, for newpolymers having improved resistance to existing and anticipateddestructive elements and forces to be encountered in their environments.For example, new polymers are needed to meet the requirements forthermally stable rain-'erosion-resistant coatings for radomes andleading edges of highspeed aircraft. In addition to being thermallystable and rain-erosion-resistant, these coatings must be flexible,radar transparent, and must resist degradation upon exposure to fuels,lubricants, organic solvents, ultraviolet radiation, and extreme weatherconditions. Relative ease of fabrication is yet another highly desirablefeature of these coatings.

Certain silicon-containing polymers are heat and solvent resistant andmay be cured at moderate conditions, but they generally have poorrain-erosion-resistance. Certain fluorocarbon polymers are also heat andsolvent resistant, but they do not cure at moderate conditions.

SUMMARY OF THE INVENTION Accordingly, an object of the present inventionis to provide novel polymers having desired characteristics as discussedabove.

Another object of the present invention is to provide novel polymerscontaining both silicon and fluorine atoms'to combine the advantages ofknown silicon-containin g and fluorine-containing polymers withoutincurring or substantially alleviating their disadvantages.

Another object of the present invention is to provide novel thermallystable oxysilylene fluorochemical polymers having improvedrain-erosion-resistance and which may be cured at moderate conditions.

Yet another object of the present invention is to provide processes forpreparing these polymers.

These and other objects of the present invention will be apparent fromthe following:

In accordance with the present invention, oxysilylene fluorochemicalpolymers are provided which have recurring units represented orexemplified by the structural formula:

in the above formula, R represents a covalent bond or divalent radicalsuch as a radical represented by the structural formula R and Rrepresent divalent radicals such as alkylene, alkenylene, cycloalkylene,cycloalkenylene, arylene, arylalkylene, alkylarylene, oxyalkylene, oriminoalkylene. Further, R R R and R represent monovalent radicals suchas methyl, ethyl, or phenyl.

The process for making the above-defined oxysilylene fluorochemicalpolymers comprises reacting one or more fluorochemical diols containingtwo pairs of trifluoromethyl groups, each pair being attached directlyto a carbon atom having a hydroxy group attached thereto, and one ormore silylamino compounds having two amino groups each attached directlyto a silicon atom. Alternatively, a dialkali metal salt of the diol maybe reacted with a dichloride corresponding to the silylamino compound toyield the oxysilylene fluorochemical polymers of the present invention.

The essence of the present invention is the discovery that these diolsor their corresponding dialkali metal salts can be reacted with thesilylamino compounds or their corresponding dichlorides to give stablepolymers. In contrast to the present invention, certain fluorocarbondiols such as hexafluoropentane diol and tetrafluorohydroquinone whenreacted with silylamino compounds such asbis(dimethylamino)dirnethyl-silane yield a polymer which rapidlyhydrolyzes, i.e., decomposes, upon exposure to the atmosphere.

Other aspects and advantages of the present invention will be apparentfrom the following description of the preferred embodiments:

DESCRIPTION OF THE PREFERRED EMBODIMENTS Any fluorochemical diolcontaining two pairs of trifluoro-methyl groups, each pair beingattached directly to a carbon atom having a hydroxy group attachedthereto, may be used in the present invention to prepare the desiredoxysilylene fluorochemical polymers.

The fluorochemical diols may be represented by the general structuralformula:

where R, is a divalent organic radical which may be an alkylene,alkenylene, cycloalkylene, cycloalkenylene, arylene, arylalkylene,arylalkenylene, alkenylarylene, oxyalkenylene, oxyarylene,oxyalkyarylene alkylarylene, oxyalkylene, iminoalkylene, andiminoarylene. The alkyl, alkylene and alkenylene groups are portions ofthe groups preferably contain from two to six carbon atoms.

The corresponding dialkali metal salts of these diols may also bereacted with the below described silyl dichlorides to yield polymers ofthe present invention. The term corresponding dialkali metal salts isused herein to define these compounds having the general structuralformula set forth above except that each hydroxy group (OH) is replacedby an alkali metal alkoxide group (e.g., ONa). For example, the sodium,potassium and lithium salts of the diols may be used. Mixed alkali metalsalts, e.g., the half sodium-half potassium salt, are also contemplatedin the present invention.

The most preferred fluorochemical diols are the HFApropylonc adductThese isobutylene and propylene adducts of hexafluoroacetone are mostpreferred because they have been found to give flexible and the moststable polymers when reacted with the below described silylaminocompounds.

Non-limiting examples of other specific fluorochemical diols which maybe used in the present invention include OII: CH;

no nus-Q-rFQ-ow Fa)20I IIO (CFa) :CCHzOCHzCKJFa) zOII nowmnoomQowmnonand their corresponding dialkali metal salts.

The manner in which the fluorochemical diol is prepared is well knownand does not form a part of the present invention. See, for example,U.S. Pat No.

3,324,187 and J. Org. Chem, 33, 2302-2310 1968).

Any silylamino compound having two amino groups each attached directlyto a silicon atom may be reacted with the fluorochemical diolsheretofore described to prepare the desired oxysilylene fluorochemicalpolymers.

The silylamino compounds may be represented by the general structuralformulas:

where R R R and R represent monovalent radicals which may be methyl,ethyl, or phenyl; wherein R represents a divalent radical which may bealkylene, alkenylene, cycloalkylene, cycloalkenylene, arylene,arylalkylene, arylalkenylene, alkenylarylene, oxyalkenylene, oxyarylene,oxyalkyarylene, alkylarylene, oxyalkylene, iminoalkylene, andiminoarylene; and wherein X, and X represent hydrogen, an aryl group, oran alkyl group. Preferably, R is arylene, and X and X are alkyl groupshaving from one to two carbon atoms, preferably methyl.

The corresponding silyl dichlorides of these silylamino compounds may beconcurrently used with the silylamino compounds to react with the diols,and may also be used above to react with the heretofore describeddialkali metal salts of the fluorochemical diols to yield the polymersof the present invention. The terms corresponding silyl dichloride andcorresponding dichloride are used herein to define those silyl compoundshaving the structural formula set forth above except that each aminogroup (X,X N) is replaced by a chloro (Cl) group.

The most preferred silylamino compounds are 1,4-bis(dimethyl-aminodimethylsilyl)benzene andbis(dimethylamino)dimethylsilane which have been found to give the moststable polymers when reacted with the above-described fluorochemicaldiols.

Non-limiting examples of other specific silylamino compounds which maybe used in the present invention include CH3 CH3 CH3 E (CHahN-Sf- Si-N(CH5):

CH3 H The manner in which the silylamino compound is prepared is wellknown and does not form a part of the present invention. See, forexample, the preparation of bis(dimethylamino)dimethylsilane describedby H.1-l. Anderson, J. Am. Chem. Soc., 75, pp. 995-997 (1953).

The above-described fluorochemical diols and silylamino compounds may befurther substituted with small non-reactive substituents such as methylor ethyl groups, or other small substituents which are not capable ofreaction under the conditions of reaction or polymerization of thefluorochemical diol with the silylamino compound.

The oxysilylene fluorochemical polymers of the present invention may bemade by a number of different specific processes or routes.

For example, the polymers may be made by a one stage or two stageprocedure, preferably using organic solvent as the reaction orpolymerization medium for the reactants. Alternatively, the one or twostage polymerization may be conducted in the absence of any solvent.

Suitable solvents include normally liquid organic solvents such as thelower aliphatic ethers, e.g.,diethyl ether, l,4-dioxane, andtetrahydrofuran; the lower fluorinated aliphatic ethers, e.g., (n-C F O,FREON E2 (E1. duPont de Nemours'& Co.); the aromatic hydrocarbons, e.g.,benzene, toluene, and xylene; and the chlorinated methanes and ethanes,e.g., carbon tetrachloride, l,l,l-trichloroethane, and 1,1,2-trichloroethane. The term normally liquidis used herein to indicate aliquid state at 25 C and 760 mm Hg pressure.

Tetrahydrofuran and perfluorinated (n-dibutyl)ether are the mostpreferred solvents.

The one stage procedure can be carried out by dissolving and heating thereactants in a solvent polymerization medium at temperatures of about 25to 160 C, and more preferably at about 60 to 140 C for sufficient timeto produce the desired molecular weight polymer, or until no furtherreaction is detected. Generally, such reaction periods range from about1 to 24 hours, and more usually 4 to 16 hours, depending on theparticular reactants used, temperatures employed, and other particularprocess parameters. The resulting polymer may be isolated from thereaction medium by evaporating the solvent or precipitating the polymerby the addition of a non-solvent such as methanol. When the alkali metalsalt of the diol is used with the silyl dichloride, the sodium chlorideby-product may be removed by filtration before the polymer is isolated.

The reaction is usually conducted in the presence of an inert atmosphereof nitrogen, argon or the like, and under substantially moisture-freeconditions, i.e., in an atmosphere containing no or little water, e.g.,less than about ppm water vapor.

Whenever a solvent polymerization medium is used, from about 0.5 to 10parts, and preferably from about 1 to 3 parts, of the solventpolymerization medium is provided per part of the reactants.

Whenever the polymerization is conducted in the absence of solvent, thesame ranges of temperatures and reaction times, and the same kinds ofinert atmosphere may be used as described above.

To maximize yield and minimize production of cyclic products when usingthe one state procedure, the fluorochemical diol may be presentinitially in a stoichiometrically excess amount with respect to thesilylamino compound, which is thereafter incrementally added to thereaction medium until at least substan- 7 tially equal molar amounts ofdiol and silylamino reactants have been added. For example, the diol maybe present initially as the sole reactant in the reaction zone, and thesilylamino compound may be added in increments of about 10 to 20 percentover a period of about 0.5 to 24 hours; or the diol may be presentinitially in a to percent excess, and the silylamino added in incrementsof l to 2 percent over the same time period.

In the two stage reaction procedure, the fluorochemical diol and thesilylamino compound such as bis(dimethylamino)dimethylsilane may firstbe reacted to obtain a silylated adduct represented by the structuralformula The silylated adduct is then reacted with additional silylaminocompound to yield a polymer of the present invention. This two stageprocedure is preferably used whenever the predominant reaction productof a particular fluorochemical diol and a particular silylamino compoundis a cyclic or non-polymeric product. This two stage procedure may bemost advantageous whenever the silylamino compound to be reacted isbis(dimethylamino) dimethylsilane.

As stated above, the two stage procedure can be carried out in a solventreaction medium or in the absence of solvent. For example, the two stageprocedure can be carried out by dissolving and heating the reactants ina solvent polymerization medium at temperatures of about 25 to 160 C,and more preferably at about 60 to 140 C for a sufficient time toproduce the corresponding silylated adduct. Generally, such reactionperiods range from about 1 to 50 hours, and more usually 4 to 6 hours.The resulting silylated adduct may be isolated by distillation orprecipitation with methanol.

The silylated adduct is then reacted with additional silylamino compoundby introduction into a second stage polymerization zone and heating attemperatures of about 25 to 160 C, preferably 60 to 140 C, undersubstantially moisture-free conditions, as described above, to yield anoxysilylene fluorochemical polymer. Generally, the second stage reactionperiods range from about 1 to 24 hours, and more typically to 4 to 16hours.

The above one and two stage polymerization processes may be conducted atatmospheric, superatmospheric, or subatmospheric pressures in a batch,semi-continuous, or continuous manner.

The molecular weight of the oxysilylene fluorochemical polymers producedherein may be indicated by an inherent viscosity (I.V.) of at leastabout 0.05, e.g.,about 0.1 to 1.0.

The inherent viscosity, (I.V.), as used in the present specification andclaims, is measured at C at a concentration of 1.0 gram of polymer perdeciliter of tetrahydrofuran solvent. The viscosity of the polymersolution is measured relative to that of the solvent and the inherentviscosity is determined from the following equation:

In the above formula, V, is the efflux time of the solution, V is theefflux time of the solvent, and C is the concentration expressed ingrams of polymer per deciliter of solution. As is known in the polymerart, inherent viscosity provides a measure of the molecular weight ofthe polymer, with higher inherent viscosities indicating highermolecular weight and vice versa.

Depending upon the reactants used and the molecular weights of theproducts, the polymers may range from oily liquids or soft waxes tostrong elastomers or hard plastics. The polymers may be useful asdielectric fluids, heat exchange oils, lubricants, coatings, adhesives,binders, sealants, gaskets, encapsulating resins, films, fibers, tubing,and molded articles.

It will also be apparent that other modifying agents such as fillers,e.g., carbon black, silica, glass fibers, etc., as well as heat andlight stabilizers, dyes, and pigments may be incorporated into thepolymers without departing from the scope of the invention.

The invention is additionally illustrated by the following examples; allparts and percentages are by weight in the examples, as well as in otherparts of the specification and claims, unless otherwise indicated.

EXAMPLE 1 Run 1 This run illustrates the preparation and properties ofAn Oxysilylene Fluorochemical Polymer Of The Present Invention andobtained from the reaction of hexafluoroacetone-isobutylene adduct (1)and 1,4- bis(dimethylaminodimethylsilyl)benzene. The oxysilylenefluorochemical polymer was prepared by placing 3.00 parts of the adductand 5 parts of reagent grade xylene in a stirred reactor through whichnitrogen flux at substantially atmospheric pressure was passing. To thisreactor, 1 .77 parts of l ,4- bis(dimethylaminodimethylsilyl) benzenewere added. The resultant reaction mixture was heated to about 155 C,with the xylene being refluxed for 1 hour at that temperature while aninitial gas evolution took place. At that point, 0.018 parts of thesilylamino compound were added every 20 minutes until the total amountof l,4-bis(dimethylaminodimethylsilyl)benzene amounted to 2.18 parts.The solution was then refluxed for 16 hours. The inherent viscosity ofthe polymer was found at that point to be 0.05. The addition ofsilylamino compound was resumed until an additional 0.21 parts had beenadded, and the mixture was refluxed at C for 16 hours. The resultantinherent viscosity of the polymer was 0.129. The reaction was thenterminated by adding 2 parts of water and continuing to flux for 2hours. After cooling, excess water and a trace of brown insolublematerial were removed by centrifugation. The inherent viscosity of thepolymer was measured and found to be 0.13. The elemental analysis of thepolymer substantially agreed with the theoretical calculation forc,,ii,,i=,,o,si,, a polymer having recurring units of the formula Usingstandard gel permeation chromatography techniques, the number averagemolecular weight was calculated to be about 1 1,000, and the weightaverage molecular weight was calculated to be about 30,000. Run 2Thisrun illustrates the preparation and properties of A Polymer Not OfThe Present Invention and prepared from a fluorinated linear alkyleneglycol (1,5-dihydroxy-2,2,3,3,4,4,-hexafluoropentane diol) andbis(dimethylamino)dimethylsilane. The polymerization procedure was thesame as in Run 1 except that dioxane was used as the solvent, and thesilylamine was added to the refluxing dioxane solution at a rate of 0.05milliliters per minute period over a total period of 2 hours, withrefluxing being continued thereafter for 3.5

hours after the calculated stoichiometric amount of dimethylsilane hadbeen added. The resulting polymer had an inherentviscosity of 0.29. Thispolymer was a viscous oil but its viscosity decreased visibly uponexposure to ambient atmospheric air (25 C and 760 millimeters mercury).Afterthe oil wasexposed to the air for several days, crystals of theoriginal diol formed in the oil. The polymer was judged to be toosensitive to moist airto be useful. Run 3 Y The run illustratesthepreparation of A Polymer Not Of The Present Invention and preparedfrom a fluorinated aromatic diol (tetrafluorohydroquinone) andbis(dimethylamino)dimethylsilane. The polymer was prepared from thesereactants in accordance with the procedure used in Run 2. After removalof the solvent, the resulting polymer was obtained as a dark brownsticky grease which changed rapidly to a friable mass upon exposure toambient air. This polymer was also judged to be too sensitive tomoisture in the air to be useful. Run 4 1 Thus run illustrates thepreparation of A Polymer Not.Of The Present Invention and prepared froma fluorinated aromatic diol (tetrafluorohydroquinone) andl,4-bis(dimethylaminodimethylsilyl)-benzene. The same proceduredescribed in Run 2 for the polymerization of tetrafluorohydroquinone andbis(dimethylamino)dimethylsilane was tried. The polymeric productchanged rapidly to a dark brown, friable mass upon exposure to ambientair. Again, this polymer was judged too sensitive to moisture in the airto be useful.

EXAMPLE II The polymers of the present invention may be cured intoelastomers using a wide variety of well known curing agents. Forexample, the polymers of the present invention may be cured according toU.S. Pat. No. 2,843,555 which is incorporated herein by reference. Toillustrate, an oxysilylene fluorochemical polymer having an inherentviscosity of 0. l 4 was prepared in accordance with Run 1 of Example Iexcept that the polymer, dissolved in xylene, was precipitated by theaddition of methanol.

Five parts of this polymer were mixed with 30 parts of xylene and 0.78parts of partially hydrolyzed ethyl silicate (Ethyl Silicate 40 fromUnion Carbide Corporation). The resulting solution was then mixed with0.20 parts of dibutyltin diacetate. The resulting mixture was stirredthoroughly and poured into a flat bottom aluminum container. The castfilm gelled in about 2 hours and reached maximum strength in 5 days.Fortythree days after being cast, the nominal tensile strength of thefilm was 1,240 psi and its elongation at break was 265 percent giving anultimate tensile strength of 3,300 psi. The film was rubbery at roomtemperature C) but it became stiff at about 0 C.

To determine its solvent resistance, a small piece of cured polymermeasuring 0.15 inches by 0.20 inches was placed on a glass cover slideover a scale with divisions of 0.01 inches. The initial overall lengthof the cured polymer was measured under a binocular microscope, and asmall steel cylinder with open ends was placed on the glass to enclosethe sample. Solvent was poured into the cylinder and the sample wasobserved until the length became constant. The ratio of the swollen tothe unswollen length is reported as the swelling ratio; The results aresummarized in Table l with similar data on the swelling of a chloropreneelastomer (neoprene N83) and a silicone elastomer (silicone K1213,peroxide cured).

As can be seen from the above table, the polymer of the presentinvention had good solvent resistance comparable to that of neoprene andsilicone elastomers which are frequently employed in applications wheresolvent resistance is important.

Many polymers containing C-O-Si bond are known to be hydrolyticallyunstable. However, the oxysilylene fluorochemical polymer of thisExample was not degraded by boiling for one hour in 1 percent aqueoushydrochloric acid at C or in 1 percent sodium hydroxide at 100 C.Further, a strip of the cured polymer was stable to boiling water at 100C over a period of 2 hours.

Thermogravimetric analysis of the polymer showed that only 10 percent ofthe weight of the polymer had been lost when the temperature reached 400C at a heating rate of 10 C per minute in nitrogen. This analysis placesthe polymer among the most stable elastomers known.

EXAMPLE Ill Run 1 of Example I was repeated except that thehexafluoroacetone-propylene adduct was used instead of the isobutyleneadduct. The inherent viscosity of the resulting polymer was 0.14.

EXAMPLE IV Run 1 This run illustrates the successful'production of anoxysilylene fluorochemical polymer from hexafluoroacetone-propyleneadduct and bis(dimethylamino)dimethylsilane by carrying out the reactionin two stages. In the first stage, an intermediate diol was prepared byadding the diaminosilane in small increments of about 0.1 parts perminute to a stirred reactor containing 94 parts ofhexafluoroacetone-propylene adduct. After adding about 9.1 parts of thedimethylsilane, a silicon-containing diol was isolated by distillationof the reaction mixture of about 93 -C and 0.03 millimeters mercury. Inthe second stage, nine parts of the resulting diol was reacted with 0.6parts of additional bis(dimethylamino)dimethylsilane at 140 C for 14hours. The resulting polymer had an inherent viscosity of 0.08. Run 2This comparative run illustrates an attempted onestage polymerization ofhexafluoroacetone-isobutylene adduct withbis(dimethyl-amino)dimethylsilane which resulted in the principalproduct being a cyclic ether having the formula CH2 g HzC \CH F9293 2 lC(CFa)! Twenty parts of the diaminosilane as a 35 percent solution indioxane was added slowly to 50 parts of a refluxing 35 percent dioxanesolution of the adduct. Refluxing was at 100 C which was allowed tocontinue for 2 hours. A small amount of low molecular weight polymer wasproduced, but the principal product was the cyclic ether. Thus, in thisinstance a two stage reaction procedure such as described in Run 1 abovemust be used to prevent formation of the cyclic product.

EXAMPLE V This Example illustrates the preparation of a useful polymerby the reaction of the disodium salt of hexafluoroacetone-propyleneadduct with dimethyldichlorosilane. To a stirred reactor containing 9.83parts of the disodium salt dissolved in 50 parts of ether was added 3.03parts of freshly distilled dimethyldichlorosilane. The precipitateformed immediately was filtered off and the clear ether solution wasevaporated to yield the polymer in the form of an oil. This oil washeated to 160 C at 0.05 millimeters mercury pressure to distill offcyclic by-products. The inherent viscosity of the resulting product was0.01.

EXAMPLE VI This example shows the use of a combination of diaminosilaneand dichlorosilane in the reaction with the diol. It is believed thatthe combination of a diaminosilane and dichlorosilane gives a highermolecular weight polymer by removing the amine as the hydrochloride,which is insoluble in the fluorinated either solvent.

The hexafluoroacetone-propylene adduct, 13.3 parts, was dissolved in 42parts of Freon E-2 (a fluorinated ether of E. l. du Pont de Nemours, andCo.,

Inc.) in a reactor through which nitrogen was flowing slowly atsubstantially atmospheric pressure. To this reactor, 1.29 parts ofbis(dimethylamino)dimethylsilane and 1.14 parts ofdimethyl-dichlorosilane were added. The resultant reaction mixture washeated to reflux temperature (104 C). While the solution was refluxing,0.011 parts of the dichlorosilane and 0.013 parts of the diaminosilanewere added alternately and repetitively until the total amount of thedichlorosilane was 1.36 parts and of the diaminosilane was 1.55 parts.The resulting solution of polymer was cooled and separated from the saltlayer by decantation. A sample of the polymer was withdrawn and found tohave an inherent viscosity of 0.07 dl/g. The polymer end-groups werehydrolyzed by adding 2 parts of water to the solution and refluxing for1 hour. The solution was allowed to cool, excess water was removed bycentrifugation, and the last traces of water were removed by drying thesolution over anhydrous sodium sulfate. After adding, successively, anadditional 0.10 parts of diaminosilane and 0.13 parts of dichlorosilaneto the refluxing solution of polymer that had been hydrolyzed, thepolymer was found to have an inherent viscosity of 0. 10 dl/g. Byrepeating the hydrolysis procedure and then adding an additional 0.14parts diaminosilane and allowing the mixture to reflux overnight, apolymer was obtained that had an inherent viscosity of 0.20 dl/g.Additional dichlorosilane, 0.20 parts, was then added, and the solutionwas refluxed for 1 hour. Finally, water, 2 parts, was added to hydrolyzethe end-groups, the excess water was removed by centrifugation, and thepolymer was purified by precipitation as follows: 17 parts oftetrahydrofuran was added to 16 parts of the polymer solution, whichcontained 4.4 parts polymer. Methanol, 20 parts, was added to thestirred solution and 3.2 parts of polymer with an inherent viscosity of0.26 dl/g precipitated.

The glass transition temperature of the polymer was 50 C.

The principles, preferred embodiments, and modes of operation of thepresent invention have been described in the foregoing specification.The invention which is intended to be protected herein, however, is notto be construed as limited to the particular forms disclosed, sincethese are to be regarded as illustrative rather than restrictive.Variations and changes may be made by those skilled in the art withoutdeparting from the spirit of the present invention set forth in thefollowing claims.

I claim:

1. An oxysilylene fluorochemical polymer having recurring unitsrepresented by the structural formula wherein R represents a covalentbond or a divalent radical is aryl, and wherein R R R and R are methyl.

3. The polymer of claim 1 wherein R represents a covalent bond andwherein R represents alkylene or alkenylene of from two to six carbonatoms, and wherein R and R are methyl.

4. Thepolymer of claim 1 wherein R represents and wherein R representsalkylene or alkenylene of from two to six carbon atoms, and wherein R RR and R are methyl.

5. An oxysilylene fluorochemical polymer consisting essentially ofrecurring units represented by the structural formula L JFa (BFa Illa-Iwherein R represents a covalent bond or divalent radical and wherein Ris a divalent radical selected from the group consisting of 6. A processfor making an oxysilylene fluorochemi cal polymer, which processcomprises reacting by contacting in a solvent reaction medium and undersubstantially moisture-free conditions,

A. at least one fluorochemical diolrepresented by the structural formulaF3 or, no-o-In-(f-orr 14 and thereafter reacting the silylated adductwith additional bis(dimethylamino)-dimethylsilane to yield a polymerconsisting essentially of recurring units represented by the structuralformula I (l) l; (llF; Ulla l 7. A process for making oxysilylenefluorochemical polymers, which process comprises reacting by contactingin a substantially moisturefree reaction zone at a temperature of about25 to 160 C and in a reactant (A): reactant (B) mole ratio ofabout 0.8:1to 12:1 A. at least one fluorochemical diol represented by thestructural formula 0 i 0 Fa IrocR',o.o1-r

C F 0 Fa wherein R represents a divalent radical selected from the groupconsisting of alkylene, alkenylene, cycloalkylene, cycloalkenylene,arylene, arylalkylene, arylalkenylene, alkenylarylene, oxyalkenylene,oxyarylene, oxyalkyarylene', alkylarylene, oxyalkylene, iminoalkylene,and iminoarylene, and

B. at least one silylamino compound selected from the class consistingof Illa '10 xlxzN-si-Nxlx, and XiX2N?iR5SiNXlXj wherein R R R and Rrepresent monovalent radicals selected from the group consisting ofmethyl, ethyl, and phenyl; wherein R represents a divalent radicalselected from the group consisting of alkylene, alkenylene,cycloalkylene, cycloalkenylene, arylene, arylalkylene, arylalkenylene,alkenylarylene, oxyalkenylene, oxyarylene, oxyalkyarylene, alkylarylene,oxyalkylene, iminoalkylene, and iminoarylene, and wherein X and X areselected from the group consisting of hydrogen, and alkyl group and anaryl group.

8. The process of claim 7 wherein for each part of reactants about 0.5to 10 parts of an organic solvent polymerization medium are present inthe reaction zone, the medium being selected from the group consistingof the normally liquid lower aliphatic ethers, lower fluorinatedaliphatic ethers, aromatic hydrocarbons, and the chlorinated methanesand ethanes.

9. The process of claim 7 wherein the temperature is about 60 to C andthe mole ratio is about 0.921 to 10:1.

10. A process for making oxysilylene fluorochernical polymers havingrecurring units represented by the structural formula equimolar amountsof C r a Ito-('J-lh-JJ-On C F; C F3 and wherein R is a divalent radicalselected from the group consisting of CH] H:

and (b) bis(dimethylamino)dimethylsilane or 1,4-bis(dimethylamino-dimethylsilyl)benzene, until a polymer having an I.V.of at least about 0.05 is produced.

11. The process of claim 9 wherein for each part of reactants about 1 to3 parts of tetrahydrofuran or perfluorinated di-n-butyl etherpolymerization medium are present.

12. The polymer of claim 1 wherein for R the alkylene, alkenylene, andalkyl groups or portions of the groups contain up to 12 carbon atoms andthe arylene and aryl groups or portions of the groups contain up to 15carbon atoms; and wherein for R the alkylene, alkenylene, and alkylgroups or portions of the groups contain up to six carbon atoms and thearylene and aryl groups or portions of the groups contain up to 12carbon atoms.

2. The polymer of claim 1 wherein R2 is alkylene or alkenylene of fromtwo to six carbon atoms, wherein R5 is aryl, and wherein R3, R4, R6, andR7 are methyl.
 3. The polymer of claim 1 wherein R1 represents acovalent bond and wherein R2 represents alkylene or alkenylene of fromtwo to six carbon atoms, and wherein R3 and R4 are methyl.
 4. Thepolymer of claim 1 wherein R1 represents and wherein R2 representsalkylene or alkenylene of from two to six carbon atoms, and wherein R3,R4, R6 and R7 are methyl.
 5. An oxysilylene fluorochemical polymerconsisting essentially of recurring units represented by the structuralformula
 6. A process for making an oxysilylene fluorochemical polymer,which process comprises reacting by contacting in a solvent reactionmedium and under substantially moisture-free conditions, A. at least onefluorochemical diol represented by the structural formula wherein R2represents a divalent radical selected from the group consisting ofalkylene, alkenylene, cycloalkylene, cycloalkenylene, arylene,arylalkylene, arylalkenylene, alkenylarylene, oxyalkenylene, oxyarylene,oxyalkyarylene, alkylarylene, oxyalkylene, iminoalkylene, andiminoarylene; and B. bis(dimethylamino)dimethylsilane to obtain thesilylated adduct represented by the structural formula and thereafterreacting the silylated adduct with additionalbis(dimethylamino)-dimethylsilane to yield a polymer consistingessentially of recurring units represented by the structural formula 7.A process for making oxysilylene fluorochemical polymers, which processcomprises reacting by contacting in a substantially moisture-freereaction zone at a temperature of about 25* to 160* C and in a reactant(A): reactant (B) mole ratio of about 0.8:1 to 1.2:1 A. at least onefluorochemical diol represented by the structural formula wherein R2represents a divalent radical selected from the group consisting ofalkylene, alkenylene, cycloalkylene, cycloalkenylene, arylene,arylalkylene, arylalkenylene, alkenylarylene, oxyalkenylene, oxyarylene,oxyalkyarylene, alkylarylene, oxyalkylene, iminoalkylene, andiminoarylene, and B. at least one silylamino compound selected from theclass consisting of wherein R3, R4, R6, and R7 represent monovalentradicals selected from the group consisting of methyl, ethyl, andphenyl; wherein R5 represents a divalent radical selected from the groupconsisting of alkylene, alkenylene, cycloalkylene, cycloalkenylene,arylene, arylalkylene, arylalkenylene, alkenylarylene, oxyalkenylene,oxyaryleNe, oxyalkyarylene, alkylarylene, oxyalkylene, iminoalkylene,and iminoarylene, and wherein X1 and X2 are selected from the groupconsisting of hydrogen, and alkyl group and an aryl group.
 8. Theprocess of claim 7 wherein for each part of reactants about 0.5 to 10parts of an organic solvent polymerization medium are present in thereaction zone, the medium being selected from the group consisting ofthe normally liquid lower aliphatic ethers, lower fluorinated aliphaticethers, aromatic hydrocarbons, and the chlorinated methanes and ethanes.9. The process of claim 7 wherein the temperature is about 60* to 140* Cand the mole ratio is about 0.9:1 to 1.0:1.
 10. A process for makingoxysilylene fluorochemical polymers having recurring units representedby the structural formula which process comprises reacting by contactingin a substantially moisture-free organic solvent polymerization mediumat a temperature of about 60* to 140* C substantially equimolar amountsof
 11. The process of claim 9 wherein for each part of reactants about 1to 3 parts of tetrahydrofuran or perfluorinated di-n-butyl etherpolymerization medium are present.
 12. The polymer of claim 1 whereinfor R2 the alkylene, alkenylene, and alkyl groups or portions of thegroups contain up to 12 carbon atoms and the arylene and aryl groups orportions of the groups contain up to 15 carbon atoms; and wherein for R5the alkylene, alkenylene, and alkyl groups or portions of the groupscontain up to six carbon atoms and the arylene and aryl groups orportions of the groups contain up to 12 carbon atoms.